Turbine blading



June 30, 1925. 1,544,288

B. w. VAN ORMER TURBINE BLAD LNG Filed s- 15. 1923 Z5 27 DZ 29 4.0

\ v 38 as INVENTOR ATTORNEY Patented June 30, 1925 UNITED STATES PeTENTclerics BANKS W. VAN OB-MER, or noLs'o'M, PEN'NsYnvANIA, ASSIGNQR "roW'EST'INGHOUSE ELECTRIC AND MANUFACTURING GQM'BANY, A con ravention orPENNSYLVANIA.

TURBINE BLADIINGV Application filed Augu t 13, 1923. S ial No. 657,129.

To all whom it may concern:

Be it known that I, BANKs W; VAN ORMER, a citizen of the United States,and a resident of Folsom, in the county of Delaware and State ofPennsylvania, have invented a new and useful Improvement inTurbineBlading, of which the following is a specification.

My invention relates to elastic-fluid turbines, and it has for itsobject to provide low-pressure blading for apparatus of this characterwhich shall be capable of automatic adjustment to provide better pathsfor the flow of steam under variable load conditions.

A further object of my invention is to provide one or more rows ofstationary lowpressure blades, each of which is capable of flexingtransversely in accordance with the velocity of elastic fluid passingtherethrough. V

In the operation of elastic-fluid turbines it is found that, at lightloads, blading at the low-pressure end may abstract little, if any,energy from the elastic fluid owing to the fact that the energy has beenvery largely abstracted by preceding stages. Under such a condition,reduced velocity elastic fluid acts upon 'blading of the conventionaltype in such a way as to reduce the over-all efliciency of the turbineover that which would exist if the inactive blading could be omitted. Inaccordance with my invention, I provide transversely flexible capable ofautomatic adjustment in accordance with the elastic-fiuid velocity so asto provide better paths for the passage of elastic fluid under differentoperating conditions. In case of normal load, the transversely flexibleblades flex due to the impact of elastic fluid to provide curvedsurfaces such as the normal blade would have for the purpose of properlydirecting the elastic fluid to the following row of moving blades. Incase the turbine load should drop and theimpactive force of the steamagainst the transversely flexible blades should be sufficiently reduced,the latter blades will automatically straighten out so as to providepaths therebetween which shall permit of the passage of steam with aminimum degree of turning. In other words, it is the object of myinvention to stationary. low-pressure blades which are providelow-pressure bladingwhich hall be capable of discharging elastic fluidwith a minimum degree of resi's'tance'when operating at light loads.

A paratus made in accordance with m inventionis illustrated in theaccompanying drawings, forming a part of this application, in which Fig,1 is a detail sectional view of turbine blading incorporating minvention; 2 is a sectional v ew taken along the lineIL-II of Fig. 1Fig; 3- is a view similar to Fig. 1, but showing a modifiedf'orm of myinvention; and Fig. 4: is a detail View of a supporting element for usein connection with my improved blading'.

Referring now to the drawings for a better understanding of myinvention, in Fig. 1-, I show a rotor 10 carrying" moving rows of bladeslland 12 and a casing 01' stator 13 carrying a stationary row of blades14. The stationary blades 14 constitute the subject of my invention andthey will now be described.

The stationary blades 14 are shown being made up of a plurality ofhinged sections 15, 16 and 17 and, while I show three such hingedsections, it is to be understood that any suitable number may beemployed.- The hinged section 15 adjacent to the row of moving blades11, is provided with inner and outer trunnions 18 and 19 Which'fit insockets 20 and 21 provided, respectively, 'in the inner and outer rings22 and 23. The rings 22 and 23 are provided with rod portions 21 and 25which fit in openings 26 and 27 provided in the shroud ring 28 and inthe base ring 29, respectively; Springs 30 and 31"are arranged withinthe openings 26 and 27, respectively, and adjustable abut ments 32 and33 cooperate with the outer ends of such springs so that the degree ofcompression thereon may be adjusted in order to vary the tendency of therings 22 and 23 to'mo've toward the moving blades11.

The sections 17 adjacent tothe moving row of blades '12 are providedWith'tlunnions 35 and 36 which'fit openings 37 and 38, provided,respectively, in the shroud ring 28 and in the base or holding ring 29.

From the structure described, it will be and 29 are preferably made insections which are connected together by rigid radial webs 42, as may beseen from Fig-.4.

In Fig. 3, I show a further modified form of my invention in which thetransversely flexible blades are each made in a single piece, therebyavoiding the hinged construction and the necessity of using twopart,supporting-ring structures. view, I show transversely flexiblestationary blades 45 carried byinner and outer rings 46 and 47-,respectively, the ring '46 serving as a shroudring and the ring 47 beingsecured to the stator 13 in a manner similar to the ring 29 alreadyreferred to. The blades have inner trunnions 48 and outer trunnions 49which fit openings 50 and 51, respectively, in the rings 46 and 47respectively. The entrance sides of the blades 45 are provided withtrunnions 52 and 53 which fit slots 54 and 55, respectively, in therings 46 and 47, respectively. The slots 54 and 55 are of sufliclentlength sothat, when the trunnions52 and 53 are at the forward endsthereof, the blades 45 completely straighten out; When the trunnions 52and 53 occupy the rear ends of the slots 54 and 55, the blades 45 arecurved transversely. Blades made in'accordance with this modificationare made of some flexible material, preferably steel, and arenecessarily thin enough in cross-section to bend when'subjected to theimpact of motive fluid.

The operation of apparatus made in accordance wlth my inventlon 1s asfollows:

After passage through the higher pressurestagesof the turbine, elasticfluid enters the moving row of blades 11, then passesbetween thetransversely flexible blades 14, of Fig. 1,, or 45 of Fig.3, and'thenenters between the last row of moving blades 12 from which it isdischarged'to the exhaust. \Vith sufiiciently light loads, steam leavesthe moving row of blades 11 at such low velocity that the impactiveforce thereof against the transversely flexible blades is overbalanced'by the effective force of the springs 30 and 31, of Fig. 1, or of theinherent flexibility of the blades 45, of Fig; 3, with the result thatthe transversely flexible bladesstraighten out to provide substantiallystraight paths for the flow of steam therebetween.

The transversely flexible blades, there- 4 fore. serve to provide pathshaving mini- In this preceding blading. The reason for this is 7 thatpassing of relatively inert steam in curved paths between stationaryblades is avoided. With a suflicient increase in load,

the velocity of steam discharged from the i row of blades 11 increases;and, with a sufficient velocity increase, the impactive force of thesteam acting against the transversely flexible blades, becomessufiicient to cause the latter to assume a normally trans versely curvedoutline in order to present inlet edges at the proper angle for thereception of steam from the blades 11- and to present outlet edges atthe proper angle for the discharge of steam for entrance between theblades 12. 1

It is to be understood that the two types of construction for thetransversely flexible stationary blades are referred to by way ofexample only, and that any suitable construction might be used so longas these blades are capable of flexingin this way for the purposestated.I

WVhile I have shown my invention in but two forms, it will be obvious tothose skilled in the art that it is not so limited, but. is susceptibleof various other changes and modifications, without departingv from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are imposedby the prior art, or as arespecifically set forth in the appended claims.

What I claim is:

1. In a turbine, the combination of'a row of moving blades followedby arow of transversely flexible stationary blades.

2. In a turbine, the combination of a row of moving blades followed by arow of trans versely flexible blades and means for normally exerting astraightening-out influence on the latter.

3. In a turbine, a row of stationary blades each of which consists of a'plurality of hinged sections, and spring means normally tending tostraighten out the sections.

4. In a turbine, a row of stationary blades,

each of which consists ofa plurality of hinged sections, meansfor-supporting the,

rear section of each blade, and spring means tendmg normally to move theforward section so as to straighten out the hinged sectransversecontours from the inlet to the outlet edges thereof are dependent uponthe velocity of motive fluid discharged by the moving blades.

7 In a turbine, the combination of a roW of moving blades, a row ofstationary transversely adjustable blades following the mov ing bladesand Whose transverse contours are dependent upon the velocity of motivefluid discharged by the moving blades, and further blading followingblades.

said adjustable 10 In testimony whereof, I have hereunto subscribed 1923my name this 30th day of July

